Turbine engines of the type used in aircraft must be accelerated during startup to a high rotational speed to provide sufficient air compression for self-sustaining operation. Many aircraft include an Airframe Mounted Accessory Drive (AMAD) which is coupled to the turbine engine drive shaft. During startup, a drive source is coupled to the AMAD to provide the rotational energy required for starting the turbine engine. In larger aircraft, an Auxiliary Power Unit (APU) provides pneumatic power to an Air Turbine Starter (ATS) coupled to the AMAD during startup (the APU/ATS starting system). However, an APU/ATS starting system must be sized to ensure start capability for higher altitude on warmer days, which increases system weight, volume, cost, and aircraft integration impacts (e.g., duct size and fuel line size). Other aircraft may include an electrical motor (e.g., a Starter Generator or SG) having a shaft coupled directly to the AMAD to rotate the turbine engine shaft during startup. The electrical motor is typically powered by an on-board battery. However, the battery in such a system must be either significantly oversized to ensure start capability on colder days or a separate battery heater must be provided. The use of a battery heater causes startup delays while the battery is warmed and requires an external source of power. Modern aircraft designs have increased power requirements and a reduced volume for equipment.
Accordingly, there is a need for a system and method for starting an aircraft turbine engine which overcomes the problems recited above.